The present invention is related to a process for drying a water-wet mixture of materials, at least one of which is hydratable. The process involves allowing the mixture to be formed into spherical particles, flakes, ribbons or other desired configuration. The chosen forms are then cooled to a temperature sufficiently low so that the hydratable material is hydrated. To remove the unwanted waters of hydration and free water the material is heated to a temperature which allows the water to be driven off but will not cause the forms to soften and stick together. This process allows for the elimination of the need for further size reduction and the associated dust.
Dry mixtures of materials are desirable in many different situations. Included among these situations are the inclusion of a solid diluent with such materials as a dry peroxy acid compound, a surfactant compound, a dry fertilizer material or an enzyme. These materials are only a few of the many which may be benefited by the present process's ability to: (1) form particles which are quickly dried; and (2) form small particles without the usual inherent dustiness associated with such formation.
The prior art contains many references which disclose compositions containing mixtures of hydratable materials with nonhydratable materials. Most such references, however, are not concerned with utilizing the hydratable material as a drying aid and, hence, do not address the favorable and unfavorable aspects of such use. One reference which does disclose the use of hydratable material as a drying aid is U.S. Pat. No. 3,770,816, Nov. 6, 1973, to Nielsen. This reference, while disclosing the use of a hydratable material to dry a nonhydratable material, diperisophthalic acid, does not disclose that the drying process has critical parameters which must be controlled.
It is, therefore, an object of this invention to provide a superior process for the drying of a mixture of hydratable and nonhydratable materials.
This and other objects of the present invention will become apparent from the following disclosure.
All percentages and ratios used herein are by weight unless otherwise specified.